Here’s what Audi promises with the new A3 e-tron: a compact luxury hatchback that can achieve 157 mpg but also hit 138 mph. Based on the latest A3 Sportback—that’s Audi-ese for “five-door A3”—this model packs a 150-hp 1.4-liter turbocharged four-cylinder, a 102-hp electric motor, and enough battery storage to enable up to 31 miles of […]